In relation to the study of antioviposition immunity, tegumentary-associated immunoglobulins will be characterized with respect to Ig class distribution and antibody specificity, by means of immunochemical analysis of eluted Igs, the indirect fluorescent antibody test, and radio-immunodiffusion. In vivo effects of anti-schistosome antibodies will be assayed by passive transfer experiments in mice. The evolution of anti-schistosomal antibodies in long-term baboon infections will also be followed in relation to the above. S. mansoni alpha2-macroglobulin-like-rich fractions will be tested for their ability to inhibit baboon lymphocyte mitogen-induced transformation. Fractions will be tested before and after passage through anti-alpha2M immunoabsorbent columns. The immunogenic potential of a schistosomal anti-coagulant will be examined. Vaccination protection experiments will be conducted using ice. Occurrence of this anti-factor XIIa protein will be established in S. haematobium and S. japonicum worms. BIBLIOGRAPHIC REFERENCES: Tsang, V.C.W., Hubbard, W.J., and Damian, R.T.: Coagulation factor XIIa (activated Hageman Factor) inhibitor from adult Schistosoma mansoni. Amer. J. Trop. Med. Hyg., 26: 243-247, 1977. Tsand, V.C.W. and Damian, R.T.: Demonstration and mode of action of a specific inhititor for activated Hageman factor (Factor XIIa) of the intrinsic blood coagulation pathway from Schistosoma mansoni. Blood 49: 619-633, 1977.